Interfaasin salaisuuksia pohdittavaksi ajan mittaan

 Sen kyllä ymmärtää kun esim koululaiset  koulun jälkeen  purkautuvat koulusta ja  katoavat koteihinsa jasiten tulevat määrähetkellä takaisin.  Tai kun armeijassa sanotaan lepo ja joukost katoavat lomalle ja tulevat kun käsketään.

Mutta miten solun jakautumisessa kromosomit milteiuuttuvat näkymättömiksi jossain vaiheessa ja siten taas tulevat tiiveinä esiin. Mitå siinä interfaasissa organisaatiota  on että se pysyy järjestyksessä, joka voi palautua  tiiviiksi.

ArticleVolume 169, Issue 7p1214-1227.e18June 15, 2017Open access

SAF-A Regulates Interphase Chromosome Structure through Oligomerization with Chromatin-Associated RNAs

Ryu-Suke Nozawa¹ ∙ Lora Boteva¹ ∙ Dinesh C. Soares¹ ∙ … ∙ Rory R. Duncan⁴ ∙ Sutherland K. Maciver³ ∙ Nick Gilbert^1,5 nick.gilbert@ed.ac.uk … Show more

Tässä on esim ksite SAF. 

 

Summary

Higher eukaryotic chromosomes are organized into topologically constrained functional domains; however, the molecular mechanisms required to sustain these complex interphase chromatin structures are unknown. A stable matrix underpinning nuclear organization was hypothesized, but the idea was abandoned as more dynamic models of chromatin behavior became prevalent. Here, we report that scaffold attachment factor A (SAF-A), originally identified as a structural nuclear protein, interacts with chromatin-associated RNAs (caRNAs) via its RGG domain to regulate human interphase chromatin structures in a transcription-dependent manner. Mechanistically, this is dependent on SAF-A’s AAA⁺ ATPase domain, which mediates cycles of protein oligomerization with caRNAs, in response to ATP binding and hydrolysis. SAF-A oligomerization decompacts large-scale chromatin structure while SAF-A loss or monomerization promotes aberrant chromosome folding and accumulation of genome damage. Our results show that SAF-A and caRNAs form a dynamic, transcriptionally responsive chromatin mesh that organizes large-scale chromosome structures and protects the genome from instability.